Electrically shielded connector

ABSTRACT

In an electrically shielded connector, conductive material covers an outer surface of said body and is spaced away from a conductive structure included in the connector to create electrical isolation therebetween. A channel in which the connector is situated is either plugged when conductive material is applied to the connector during manufacturing or is counter bored to create the electrical isolation.

This application claims benefit of Provisional Application No.60/212,396, filed Jun. 19, 2000.

FIELD OF THE INVENTION

The present invention relates to an electrically shielded connector andin particular to an electrically shielded connector which is useful forinterfacing test equipment. Specifically, an electrically shieldedconnector is disclosed which provides good conductivity and uniformimpedance.

BACKGROUND OF THE INVENTION

To determine whether semiconductor devices have manufacturing defects,such devices are tested. Typically, an automatic test system having atest head is used to transmit appropriate signals to and receive signalsfrom the device under test (DUT). Depending upon the stage in themanufacturing cycle, a device handler or a wafer prober may be used toautomatically bring each device in turn into a position to be tested.The test head is docked with the wafer prober or device handler, and aninterface unit is provided to convey the signals between the DUT and thetest head.

In performing such tests, it is common for the test head to bothtransmit and receive signals that have low signal levels and highfrequencies. Further, with increasing complexity of devices under test,the density of signal connections between the test head and the DUTsimilarly increases.

Thus, it is useful to provide a structure which provides sufficientshielding of signals flowing between the test head and the devicehandler.

Various devices are known in the prior art to provide shielding betweenthe test head and the device handler. U.S. Pat. No. 6,037,787 (Corwith)discloses a probe interface which is formed from a plurality of metaltubes. The tubes are placed between insulative retainers. Furthermore,U.S. Pat. No. 4,724,180 (Kern) discloses an interface device in whichchannels are formed therein, and the entire device is coated with anickel coating. It is desirable to insert conducting structures (such aspogo pin structures) in the channels disclosed in each respectivepatent. It also desirable, however, for certain conducting structures tonot be in contact with the conductive layers. Thus, additionalmanufacturing steps are performed. Specifically, insulating layers (orspacers) may be needed about the conducting structures to prevent themfrom coming into contact with conductive members within the channels.

SUMMARY OF THE INVENTION

An electrically shielded connector includes: a body at least partiallycovered with conductive material and having at least two channels whichextend between opposite ends of the body; and conductive structuressituated in the channels, The conductive material covers an outersurface of the body and is spaced away from one of the conductive,structures to create electrical isolation therebetween. At least one ofthe channels is at least partially covered with conductive materialwhile at least another of the channels is non-conductive relative to theouter surface of the body. An area of one or more non-conductivematerials extends from the conductive structure in the non-conductivechannel to the conductive material covering the outer surface of thebody.

In a method of fabricating a connector, a body is provided having aplurality of non-conductive channels. One of the channels is plugged andanother of the channels is kept open. The body is exposed to conductivematerial so that the open channel is at least partially covered with theconductive material and the conductive material is excluded from theplugged channel. Conductive structures are then inserted in each of thechannels.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is perspective view which includes a cut-away portion inaccordance with an exemplary embodiment of the present invention.

FIG. 2 shows a magnified view of a portion of FIG. 1.

FIG. 3 is a perspective view of an exemplary embodiment of the presentinvention.

FIG. 4 is a magnified view of a portion of FIG. 3.

FIGS. 5–7 show exemplary pin/signal configurations.

FIG. 8 is a cross sectional view which illustrates a further exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

An exemplary embodiment of the present invention is shown in FIG. 1.FIG. 1 is a perspective view in which a portion of the object depictedhas been cut-away to show the interior. In the exemplary embodiment ofthe present invention, electrically shielded connector 50 includes anon-conductive (i.e., plastic) body 10. This plastic body may be formedfrom one or more components and may be, for example, injection molded.The outside of plastic body 10 is preferably covered with a conductivematerial. The conductive material is desirably gold. The material may beapplied, for example, by electroplating. At least two hollow channels30, 32 are formed in body 10. Channels 30, and 32 may, for example,extend between opposite ends of body 10. A plurality of conductivestructures are situated within channels 30, 32. These conductivestructures may be pogo pin structures which are well known to oneskilled in the art. As shown, for example, in FIG. 1, pogo pin structure18 may be inserted at one end of channel 30 while pogo pin structure 19may be inserted at an opposite end of channel 30. Pogo pin structures 18and 19 each have one pogo pin extending from one end, respectively.Furthermore, pogo pin structure 20 may extend all the way betweenopposite ends of channel 32. Pogo pin structure 20 may include two pogopins, extending from opposite ends of pogo pin structure 20. Thus, asshown, it is possible to have either 2 separate conductive structuresextending out of opposite ends of a channel (and not necessarily indirect mechanical contact with each other) or a single conductivestructure extending the entire length between opposite openings of achannel.

Also as shown in FIG. 1, step shoulder 6 may be molded into each end ofbody 10 to facilitate assembly with a retainer, if desired.

FIG. 2 is a magnified view of a portion of FIG. 1. As shown in FIG. 2,the inside of channel 30 may be conductively plated (i.e., with gold).Thus, gold plating 12 may be included within channel 30 so that channel30 may be used to conduct ground. The inside of channel 32 may be eitherconductively plated (i.e., with gold) or not conductively plated. Goldplating 12 may extend along the end of body 10 to form gold plating 14on the exterior end of body 10. As body 10 is formed from one or morenon-conductive components, an area of the non-conductive componentsextends from one (or either) plating within its respective channel tothe plating on the exterior of body 10.

In an exemplary embodiment of the present invention, it is preferredthat gold plating 12 extend throughout all of channel 30 so that allcross sections of channel 30 are consistent. This helps to createuniform impedance. In addition, it is also preferred to use a singlepogo pin structure as opposed to two disconnected pogo pin halvesbecause the single pogo pin structure will again provide more uniformimpedance.

FIG. 3 shows electrically shielded connector 50 in perspective view.

FIG. 4 shows a magnified portion of FIG. 3. As shown in FIG. 4, a goldplated exterior is included. Ground pogo pin 28 and signal pogo pin 40are shown. Ground pogo pin 28 conveys ground potential while signal pogopin 40 conveys a signal (e.g., a data signal). Both ground pogo pin 28and signal pogo pin 40 may be pogo pins which extend from pogo pinstructures 18 and 20, respectively. Other types of signal contacts mayalso be used. Space 22 is situated about pogo pin structure 20. There iselectrical isolation between gold plate 14 and signal pogo pin 40. Inthis document “ground” is assumed in the broad sense of being aconducting connection to a reference potential and not necessarily aconnection to earth.

FIGS. 5–7 are end views showing other possible configurations ofexemplary embodiments of the present invention. It is understood thatthese configurations are merely exemplary, and the invention is notlimited to those configurations shown. In FIG. 5, a power pin 510 issituated in the middle and there are four (or less or more) ground pins520 situated about the power pin in the middle. The purpose of thisconfiguration is to provide many ground conductors. This may minimize,for example, ground bounce. As shown in FIG. 6, a signal pin 610 may besituated in an insulated channel. A guard pin 620 may also be situatedin an insulated channel. A ground pin 630 may be situated in a platedchannel.

As shown in FIG. 7, a configuration is shown which may be desirable fordouble-ended (differential) signals. Thus, there is a ground pin 710, asignal+pin (not coupled to ground) 720, and a signal−pin (also notcoupled to ground) 730.

In an exemplary embodiment of the present invention, the edges betweenthe ends and the sides of connector 50 may be rounded or chamfered. Thiswill help to ensure that the gold plated layer is uniform andtransitions from the sides of connector 50 to the ends of connector 50.This, in turn, ensures good connectivity. Similarly, the edge betweenthe channel 30 and the ends of connector 50 may be chamfered or roundedto help ensure connectivity.

It is possible that it may be difficult to provide uniform platingthroughout the entire length of channel 30. To have desirable uniformcharacteristic impedance of the signal that travels along pogo pinstructure 20, the conducting layer (i.e., gold plating) on the inside ofchannel 30 is desirably uniform along its entire length. Therefore, inan exemplary embodiment of the present invention, it is useful to use apogo pin structure with a double-ended pogo pin, whose outer tubeeffectively lines channel 30 with conductor. It is also desirable toprovide enough plating on the end of channel 30 where it meets with theend of connector 50 to make a good electrical connection with the pogopin structure 18, and consequently pogo pin 28. The pogo pin structure18 may be inserted into channel 30 with a force or interference typefit. Alternatively, the pogo pin structure 18 could be held in place byother retention means such as conductive glue.

In an exemplary embodiment of the present invention, some space isprovided between plating 14 and channel 32. This will help preventsignal pogo pin structure 20 from shorting to ground, Space 22 which isa concentric circle depicts this spacing. Space 22 does not necessarilyhave to be circular; it could be of any other shape which might prove tobe convenient. When connector 50 is made, for example, the ends ofchannel 32 can be plugged with a plastic plug which has a shoulder thatcovers a portion of the end surface of connector 50 to keep it frombecoming plated. Thus, conductive material covers at least a portion ofthe open channel and conductive material is excluded from the pluggedchannel. Alternatively, if channel 32 is not plugged (so that conductivematerial plates the interior of channel 32), it is possible to hit theends of channel 32 with a counter sink or counter bore to remove theplating material. Alternatively, both of the above described methods maybe used.

Signal pogo pin structure 20 may be inserted into channel 32 with, forexample, a force or an interference fit. Alternatively, it could be heldin place by other retention means such as a nonconductive glue.

The tubes of the pogo pin structures may be reverse dimpled at one orboth ends. That is, a slight bulge is formed near the end of the tube.This is called a flaring or bulging and it forms a ridge with a heightof, for example, 1 to 2 mills. This may assist in assembly. The bulgeportion provides a force fit, allowing most of the tube to be slideasily into the respective channel. The diameter of the channel may bemade smaller at one end than at the other end. Then, the pogo pinstructure would slide in easily almost all of the way and then snap inwith a force type fit for the final distance of travel of insertion.

The exemplary embodiment has been described with regard to gold plating.It is understood that other material may be used for plating as long asit is conductive. Also, in place of plating, another type of conductivestructure (i.e., the tube of structure 18 or another tube) may be usedfor carrying the ground signal between opposite ends of connector 50.

As an alternative to forming hollow channels in the molded body intowhich pogo pin structures are inserted, conductive tubes may be moldedinto the body. That is, the tubes are first placed into the mold and theplastic material is then molded around them. Such tubes could be theouter tubes of pogo pin structures. Or more generally, pogo pin or othersuitable contact assemblies may be placed into the tubes. Appropriatesteps are taken to ensure that in the subsequent plating process that agood electrical connection is made between the tube in the place ofground channel 30 and the plating 14 on the exterior of plastic body 10.Also appropriate steps are taken, by for example the use of plugs ormachining steps such as described above, to ensure that no electricalconnection is made between the plating 14 and the tube in the place ofsignal channel 32.

FIG. 8 is a cross sectional view of a connector in accordance with analternative embodiment of the present invention. In this alternativeembodiment, a space 48 is defined about pogo pin structure 20. The term“space”, being used here, refers to an area in the channel, i.e.,between the inner wall of the channel and the outer wall of pogo pinstructure 20. Thus, space 48 may be an empty space filled with, forexample, air. Alternatively, space 48 may be filled with another type ofgas, a liquid, or even a solid member.

The purpose of space 48 is to provide a different characteristicimpedance than would be obtained if space 48 were not provided. Thus, ifspace 48 is not provided, then the inner walls of channel 32 and theouter walls of pogo pin structure 20 completely touch so that nothingcould be situated therebetween.

Use of space 48 may be explained through the following. If body 10 iscomprised of a non conductive material having a relative permittivitygreater than 1, and if space 48 does not exist between pogo pinstructure 20 and body 10, a resulting characteristic impedance Z₁ may beobtained. If the above structure is modified so that space 48 isincluded, pogo pin structure 20 will be situated next to a material (gassuch as air, liquid or solid) with a different relative permittivity.The resulting characteristic impedance is accordingly changed. Thegreater the distance from the outside surface of pogo pin structure 20to the insider surface of channel 32, the greater the change incharacteristic impedance.

In the exemplary embodiment shown in FIG. 8, splines 45 have been formedin channel 32 when the body was molded. These splines may run, forexample, the entire length of the channel. As shown, they serve todefine space 48 between the outer surface of pogo pin structure 20 andcertain inner surfaces of channel 32.

It is understood to one of ordinary skill in the art that othertechniques can be used to define space 48. For example, dimples or bumpscould be formed at various locations within channel 32. Washers orretainers could be used at each end of channel 32 to hold the conductorstructure at least substantially centered within channel 32 having anopening which is larger than pogo pin structure 20. The washer orretainers could be made of conducting material as long as they do notcome in contact with external plating 12. Alternatively, an insulatingsleeve of appropriate dielectric constant could be placed in space 48and about pogo pin structure 20.

With the above embodiments, connector 50 may be used to transmit andreceive data signals between, for example, a test head and a deviceunder test.

Although illustrated and described herein with reference to certainspecific embodiments, the present invention is nevertheless not intendedto be limited to the details shown. Rather, various modifications may bemade in the details within the scope and range of equivalents of theclaims and without departing from the spirit of the invention.

1. An electrically shielded connector, comprising: a body at leastpartially covered with conductive material and having at least twochannels, said at least two channels each extending between oppositeends of said body; a plurality of conductive structures situated in saidchannels; at least one of said channels at least partially covered withconductive material; at least another of said channels beingnon-conductive; said conductive material covering an outer surface ofsaid body and spaced away from one of said conductive structures tocreate electrical isolation therebetween; an area of one or morenon-conductive materials extending from said one of said conductivestructures to said conductive material covering said outer surface ofsaid body.
 2. An electrically shielded connector according to claim 1,wherein said plurality of conductive structures includes a continuousconductive structure having contacts extending out of both ends thereof.3. An electrically shielded connector according to claim 1, wherein saidplurality of conductive structures includes a partial conductivestructure having a contact extending out of only one end thereof.
 4. Anelectrically shielded connector according to claim 1, wherein a stepshoulder is formed in said body.
 5. An electrically shielded connectoraccording to claim 1, wherein said conductive material extendsthroughout all of said channel at least partially covered withconductive material.
 6. An electrically shielded connector according toclaim 1, wherein said conductive structures extend out of said body. 7.An electrically shielded connector according to claim 1, wherein an endof said another of said channels is counter bored.
 8. An electricallyshielded connector according to claim 1, wherein said conductivematerial is spaced away from said one of said conductive structureswhich is in said another of said channels.
 9. An electrically shieldedconnector according to claim 1, wherein one of said conductivestructures includes one or more pogo pin structures.
 10. An electricallyshielded connector according to claim 1, wherein at least one of saidchannels defines an area about one of said conductive structures.
 11. Anelectrically shielded connector according to claim 10, wherein a spacingmember is situated in said channel in at least a portion of said areaand in contact with said one of said conductive structures.
 12. Anelectrically shielded connector, comprising: a body covered withconductive material and having an interior conductive channel and aninterior non-conductive channel; a plurality of conductive structuresinsulated from each other and situated in said conductive channel andsaid non-conductive channel, respectively; and an area of one or morenon-conductive materials extending from said conductive structure insaid non-conductive channel to said conductive material covering saidbody.
 13. An electrically shielded connector according to claim 12,wherein said plurality of conductive structures includes a continuousconductive structure having contacts extending out of both ends thereof.14. An electrically shielded connector according to claim 12, whereinsaid plurality of conductive structures includes a conductive structurehaving a contact extending out of only one end thereof.
 15. Anelectrically shielded connector according to claim 12, wherein a stepshoulder is formed in said body.
 16. An electrically shielded connectoraccording to claim 12, wherein said conductive material extendsthroughout all of said channel at least partially covered withconductive material.
 17. An electrically shielded connector according toclaim 12, wherein said non-conductive channel includes a non-conductivesolid layer.
 18. An electrically shielded connector according to claim12, wherein an end of one of said channels is counter bored.
 19. Anelectrically shielded connector according to claim 12, wherein saidconductive material is spaced away from said one of said conductivestructures which is in said non-conductive channel.
 20. An electricallyshielded connector according to claim 12, wherein one of said conductivestructures is one or more pogo pin structures.
 21. An electricallyshielded connector according to claim 12, wherein at least one of saidchannels defines an area about one of said conductive structures.
 22. Anelectrically shielded connector according to claim 21, wherein a spacingmember is situated in said channel in at least a portion of said areaand in contact with said one of said conductive structures.
 23. Anelectrically shielded connector, comprising: a body at least partiallycovered with conductive material and having at least two channels, saidat least two channels each extending between opposite ends of said body;a plurality of conductive structures situated in said channels; each ofsaid at least two channels at least partially covered with conductivematerial; one of said channels counter bored in order to preventelectrical connection between an interior wall of said one of saidchannels and an outer surface of said body.
 24. An electrically shieldedconnector according to claim 23, wherein at least one of said channelsdefines an area about one of said conductive structures.
 25. Anelectrically shielded connector according to claim 24, wherein a spacingmember is situated in said channel in at least a portion of said areaand in contact with said one of said conductive structures.